1. Field of the Invention
The present invention relates generally to an air separation plant and more specifically to a method of and apparatus for optimizing the rate of material air supply to an air separation plant.
2. Description of the Prior Art
The main products from an air separation plant are oxygen and nitrogen. One of the essential factors for preserving the amounts and purities of these products stable is to maintain a sufficient rate of material air supply to the air separation plant. Since the demand or consumption of the oxygen and nitrogen product varies widely, because they are intermediate products having a variety of ways of use, the required amount of material air supply to the air separation plant varies correspondingly. For this reason, an air compressor for supplying the material air must be controlled frequently.
Conventionally, this control of the air compressor has been performed manually, in accordance with the required amount of material air which is determined by the ratio of the flow rate of the material air to that of the product gases. This conventional manual control of the air compressor has been found, however, to be inconvenient in that it causes an unstable material balance in the air separation plant, resulting in a large fluctuation of the purities of the product gases.